Separation of solids from tar sands extract

Abstract

Solids are separated from a tar sands extract by gravity settling or centrifugation in the presence of a liquid promoter which promotes and enhances the separation of the solid material. The liquid promoter has a characterization factor of at least 9.75, a 5 volume percent distillation temperature of at least 250° F and a 95 volume percent distillation temperature of at least 350° F and no greater than 750° F. As a result, liquid product is obtained without the necessity of preliminary coking of the entire extract.

What is claimed is: 
     
       1. A process for separating finely divided sand from a tar sands extract, comprising: separating said finely divided sand from said tar sands extract by gravity difference separation in the presence of a promoter liquid, said promoter liquid having a characterization factor of at least 9.75, a 5 volume percent distillation temperature of at least 250° F and a 95 volume percent distillation temperature of at least 350° F and no greater than 750° F and being present in an amount sufficient to promote and enhance separation of a tar sands liquid essentially free of sand; and   recovering tar sands liquid essentially free of sand.   
     
     
       2. The process of claim 1 wherein the promoter liquid is present in an amount to provide a promoter liquid to tar sands extract weight ratio of from 0.2:1 to 3.0:1. 
     
     
       3. The process of claim 2 wherein the recovered tar sands liquid contains less than 0.2%, by weight, of sand. 
     
     
       4. The process of claim 3 wherein the separation is effected by gravity setting with the recovered tar sands liquid being recovered as an overflow and a sand containing liquid being recovered as an underflow. 
     
     
       5. The process of claim 4 wherein the recovered tar sands liquid is recovered in an overall yield of at least 65 weight percent. 
     
     
       6. The process of claim 4 wherein the promoter liquid has a 5 volume percent distillation temperature of at least 310° F and a 95 volume percent distillation temperature of no greater than 600° F. 
     
     
       7. The process of claim 6 wherein the characterization factor is at least 11.0. 
     
     
       8. The process of claim 4 wherein the recovered sand containing liquid underflow is stripped of components boiling below about 800° to 1000° F to recover additional tar sands liquid essntially free of sand. 
     
     
       9. The process of claim 8 wherein the stripped underflow is coked to produce coke and further tar sands liquid essentially free of sand. 
     
     
       10. The process of claim 1 wherein at least a portion of the tar sands liquid essentially free of sand is hydrogenated to produce a crude oil. 
     
     
       11. The process of claim 10 wherein the hydrogenation is effected in the presence of a catalyst at a temperature of from 500° to 900° F and a pressure of from 500 to 5000 psig to produce a crude oil having a hydrogen to carbon atomic ratio of from 1.2:1 to 1.8:1.